Targeting the Akt signaling pathway: Exploiting curcumin's anticancer potential

Cancer is recognized as one of the leading causes of death worldwide. In recent years, advancements in early detection and expanding treatment options have contributed to a decrease in mortality rates. However, the emergence of drug-resistant cancers necessitates the exploration of innovative and more effective drugs. The Akt kinases play a central role in various signaling pathways that regulate crucial cellular processes, including cell growth, proliferation, survival, angiogenesis, and glucose metabolism. Due to frequent disruptions of the Akt signaling pathway in numerous human cancers and its broad biological implications, targeting this pathway has become a key focus in combating tumor aggressiveness and a promising avenue for therapeutic intervention. Curcumin, a compound found in turmeric, has been extensively studied for its potential as an anti-cancer agent. It demonstrates inhibitory effects on cancer initiation, progression, and metastasis by influencing various processes involved in tumor growth and development. These effects are achieved through negative regulation of transcription factors, growth factors, cytokines, protein kinases, and other oncogenic molecules. This review aims to explore curcumin's anticancer activity against different types of cancer mediated via the PI3K/Akt signaling pathway, as well as its practical applications in treatment.

miRNA, phytometabolites and disease: Connecting the dots

miRNAs are tiny noncoding ribonucleotides that function as critical regulators of gene-expression in eukaryotes. A single miRNA may be involved in the regulation of several target mRNAs forming complex cellular networks to regulate diverse aspects of development in an organism. The deregulation of miRNAs has been associated with several human diseases. Therefore, miRNA-based therapeutics is gaining interest in the pharmaceutical industry as the next-generation drugs for the cure of many diseases. Medicinal plants have also been used for the treatment of several human diseases and their curative potential is attributed to their reserve in bioactive metabolites. A role for miRNAs as regulators of the phytometabolic pathways in plants has emerged in the recent past. Experimental studies have also indicated the potential of plant encoded secondary phytometabolites to act as cross-regulators of mammalian miRNAs and transcripts to regulate human diseases (like cancer). The evidence for this cross-kingdom gene regulation through miRNA has gathered considerable enthusiasm in the scientific field, even though there are on-going debates regarding the reproducibility and the effectiveness of these findings. In this review, we provide information to connect the medicinal and gene regulatory properties of secondary phytometabolites, their regulation by miRNAs in plants and their effects on human miRNAs for regulating downstream metabolic or pathological processes. While further extensive research initiatives and good clinical evidence are required to prove or disapprove these findings, understanding of these regulations will have important implications in the potential use of synthetic or artificial miRNAs as effective alternatives for providing health benefits.

Modulation of microRNAs expression and cellular signaling pathways through curcumin as a potential therapeutical approach against ovarian cancer: A review

Short non-coding RNAs called microRNAs (miRNAs) control gene expression by either inhibiting translation or degrading messenger RNA. MiRNAs are crucial for many biological functions, and the deregulation of their expression is strongly linked to the emergence of cancer. A single miRNA controls several gene expressions, allowing it to simultaneously control a number of cellular signaling pathways. As a result, miRNAs may be used as therapeutic targets as well as biomarkers for the prognosis and diagnosis of different cancers. Recent research has shown that natural compounds like curcumin, resveratrol and quercetin exert their pro-apoptotic and/or anti-proliferative impacts by modulating one and/or more miRNAs, which inhibits the growth of cancer cells, induces apoptosis, or increases the effectiveness of conventional cancer therapies. Here, we summarize the most recent developments in curcumin's control over the expression of miRNAs and emphasize the significance of these herbal remedies as a viable strategy in the treatment and prevention of cancer.

Curcumin: a natural organic component that plays a multi-faceted role in ovarian cancer

Curcumin, a natural organic component obtained from Curcuma longa's rhizomes, shows abundant anti-tumor, antioxidant and anti-inflammatory pharmacological activities, among others. Notably the anti-tumor activity has aroused widespread attention from scholars worldwide. Numerous studies have reported that curcumin can delay ovarian cancer (OC), increase its sensitivity to chemotherapy, and reduce chemotherapy drugs' side effects. It has been shown considerable anticancer potential by promoting cell apoptosis, suppressing cell cycle progression, inducing autophagy, inhibiting tumor metastasis, and regulating enzyme activity. With an in-depth study of curcumin's anti-OC mechanism, its clinical application will have broader prospects. This review summarizes the latest studies on curcumin's anti-OC activities, and discusses the specific mechanism, hoping to provide references for further research and applications.

The Role of Natural and Semi-Synthetic Compounds in Ovarian Cancer: Updates on Mechanisms of Action, Current Trends and Perspectives

Ovarian cancer represents a major health concern for the female population: there is no obvious cause, it is frequently misdiagnosed, and it is characterized by a poor prognosis. Additionally, patients are inclined to recurrences because of metastasis and poor treatment tolerance. Combining innovative therapeutic techniques with established approaches can aid in improving treatment outcomes. Because of their multi-target actions, long application history, and widespread availability, natural compounds have particular advantages in this connection. Thus, effective therapeutic alternatives with improved patient tolerance hopefully can be identified within the world of natural and nature-derived products. Moreover, natural compounds are generally perceived to have more limited adverse effects on healthy cells or tissues, suggesting their potential role as valid treatment alternatives. In general, the anticancer mechanisms of such molecules are connected to the reduction of cell proliferation and metastasis, autophagy stimulation and improved response to chemotherapeutics. This review aims at discussing the mechanistic insights and possible targets of natural compounds against ovarian cancer, from the perspective of medicinal chemists. In addition, an overview of the pharmacology of natural products studied to date for their potential application towards ovarian cancer models is presented. The chemical aspects as well as available bioactivity data are discussed and commented on, with particular attention to the underlying molecular mechanism(s).

Curcumin enhances the anti-cancer efficacy of paclitaxel in ovarian cancer by regulating the miR-9-5p/BRCA1 axis

Background: Patients with late-stage ovarian cancer still have a very poor prognosis due to chemotherapy resistance. Curcumin has been shown to synergistically enhance the therapeutic effects of multiple chemotherapeutic agents, but the potential involvement of curcumin in ovarian cancer is largely unknown. This study aimed to investigate whether curcumin has synergistic anti-cancer effects with paclitaxel in ovarian cancer and its underlying mechanism. Methods: Ovarian cancer cell lines (SKOV3 and A2780) were treated with curcumin, alone or combined with paclitaxel. Cell viability, colony formation, EdU incorporation assays, and flow cytometry were used to assess cell proliferation, apoptosis, and cell cycle progression. The cytotoxic synergistic effect of curcumin and paclitaxel was detected by Calcusyn software. RNA immunoprecipitation assay was used to verify the interaction between miR-9-5p and BRCA1. qRT-PCR and Western blot were performed to detect gene and protein expression. Results: We found that curcumin and paclitaxel synergistically inhibited proliferation and promoted apoptosis in ovarian cancer cells. Furthermore, curcumin and paclitaxel combination resulted in decreased miR-9-5p expression and increased BRCA1 expression. Functionally, miR-9-5p overexpression counteracted the synergistic effect of curcumin and paclitaxel on cell proliferation and apoptosis by targeting BRCA1. Meanwhile, in vivo experiments revealed that curcumin and paclitaxel combination dramatically suppressed the growth of transplanted tumors, while miR-9-5p mimics eliminated the growth inhibition of xenografts induced by the combined treatment. Conclusion: Curcumin enhanced the anti-cancer efficacy of paclitaxel in ovarian cancer by regulating the miR-9-5p/BRCA1 axis. These findings provide strong evidence for clinical investigation of curcumin and paclitaxel combination as a novel strategy for ovarian cancer patients, and identify miR-9-5p and BRCA1 as key targets for regulating sensitivity to this therapy.

Curcumin Inhibits Proliferation of Renal Cell Carcinoma in vitro and in vivo by Regulating miR-148/ADAMTS18 through Suppressing Autophagy

OBJECTIVE

To explore the effect of curcumin on the proliferation of renal cell carcinoma and analyze its regulation mechanism.

METHODS

In RCC cell lines of A498 and 786-O, the effects of curcumin (2.5, 5, 10 µ mo/L) on the proliferation were analyzed by Annexin V+PI staining. Besides, A498 was inoculated into nude mice to establish tumorigenic models, and the model mice were treated with different concentrations of curcumin (100, 200, and 400 mg/kg), once daily for 30 days. Then the tumor diameter was measured, the tumor cells were observed by hematoxylin-eosin staining, and the protein expressions of miR-148 and ADAMTS18 were detected by immunohistochemistry. In vitro, after transfection of miR-148 mimics, miR-148 inhibitor or si-ADAMTS18 in cell lines, the expression of ADAMTS18 was examined by Western blotting and the cell survival rate was analyzed using MTT. Subsequently, Western blot analysis was again used to examine the autophagy phenomenon by measuring the relative expression level of LC3-II/LC3-I; autophagy-associated genes, including those of Beclin-1 and ATG5, were also examined when miR-148 was silenced in both cell lines with curcumin treatment.

RESULTS

Curcumin could inhibit the proliferation of RCC in cell lines and nude mice. The expression of miR-148 and ADAMTS18 was upregulated after curcumin treatment both in vitro and in vivo (P<0.05). The cell survival rate was dramatically declined upon miR-148 or ADAMTS18 upregulated. However, si-ADAMTS18 treatment or miR-148 inhibitor reversed these results, that is, both of them promoted the cell survival rate.

CONCLUSION

Curcumin can inhibit the proliferation of renal cell carcinoma by regulating the miR-148/ ADAMTS18 axis through the suppression of autophagy in vitro and in vivo. There may exist a positive feedback loop between miR-148 and ADAMTS18 gene in RCC.

Contribution of Non-Coding RNAs to Anticancer Effects of Dietary Polyphenols: Chlorogenic Acid, Curcumin, Epigallocatechin-3-Gallate, Genistein, Quercetin and Resveratrol

Growing evidence has been accumulated to show the anticancer effects of daily consumption of polyphenols. These dietary polyphenols include chlorogenic acid, curcumin, epigallocatechin-3-O-gallate, genistein, quercetin, and resveratrol. These polyphenols have similar chemical and biological properties in that they can act as antioxidants and exert the anticancer effects via cell signaling pathways involving their reactive oxygen species (ROS)-scavenging activity. These polyphenols may also act as pro-oxidants under certain conditions, especially at high concentrations. Epigenetic modifications, including dysregulation of noncoding RNAs (ncRNAs) such as microRNAs, long noncoding RNAs, and circular RNAs are now known to be involved in the anticancer effects of polyphenols. These polyphenols can modulate the expression/activity of the component molecules in ROS-scavenger-triggered anticancer pathways (RSTAPs) by increasing the expression of tumor-suppressive ncRNAs and decreasing the expression of oncogenic ncRNAs in general. Multiple ncRNAs are similarly modulated by multiple polyphenols. Many of the targets of ncRNAs affected by these polyphenols are components of RSTAPs. Therefore, ncRNA modulation may enhance the anticancer effects of polyphenols via RSTAPs in an additive or synergistic manner, although other mechanisms may be operating as well.

A Comprehensive Review on the Benefits and Problems of Curcumin with Respect to Human Health

Curcumin is the most important active component in turmeric extracts. Curcumin, a natural monomer from plants has received a considerable attention as a dietary supplement, exhibiting evident activity in a wide range of human pathological conditions. In general, curcumin is beneficial to human health, demonstrating pharmacological activities of anti-inflammation and antioxidation, as well as antitumor and immune regulation activities. Curcumin also presents therapeutic potential in neurodegenerative, cardiovascular and cerebrovascular diseases. In this review article, we summarize the advancements made in recent years with respect to curcumin as a biologically active agent in malignant tumors, Alzheimer’s disease (AD), hematological diseases and viral infectious diseases. We also focus on problems associated with curcumin from basic research to clinical translation, such as its low solubility, leading to poor bioavailability, as well as the controversy surrounding the association between curcumin purity and effect. Through a review and summary of the clinical research on curcumin and case reports of adverse effects, we found that the clinical transformation of curcumin is not successful, and excessive intake of curcumin may have adverse effects on the kidneys, heart, liver, blood and immune system, which leads us to warn that curcumin has a long way to go from basic research to application transformation.

Involvement of microRNA modifications in anticancer effects of major polyphenols from green tea, coffee, wine, and curry

Epidemiological studies have shown that consumption of green tea, coffee, wine, and curry may contribute to a reduced risk of various cancers. However, there are some cancer site-specific differences in their effects; for example, the consumption of tea or wine may reduce bladder cancer risk, whereas coffee consumption may increase the risk. Animal and cell-based experiments have been used to elucidate the anticancer mechanisms of these compounds, with reactive oxygen species (ROS)-based mechanisms emerging as likely candidates. Chlorogenic acid (CGA), curcumin (CUR), epigallocatechin gallate (EGCG), and resveratrol (RSV) can act as antioxidants that activate AMP-activated protein kinase (AMPK) to downregulate ROS, and as prooxidants to generate ROS, leading to the downregulation of NF-κB. Polyphenols can modulate miRNA (miR) expression, with these dietary polyphenols shown to downregulate tumor-promoting miR-21. CUR, EGCG, and RSV can upregulate tumor-suppressing miR-16, 34a, 145, and 200c, but downregulate tumor-promoting miR-25a. CGA, EGCG, and RSV downregulate tumor-suppressing miR-20a, 93, and 106b. The effects of miRs may combine with ROS-mediated pathways, enhancing the anticancer effects of these polyphenols. More precise analysis is needed to determine how the different modulations of miRs by polyphenols relate to the cancer site-specific differences found in epidemiological studies related to the consumption of foods containing these polyphenols.

Molecular Targets of Curcumin and Its Therapeutic Potential for Ovarian Cancer

Ovarian cancer is the fifth most common gynecological cancer in women globally. Conventional chemotherapy is the first therapeutic approach in the treatment of ovarian cancer, but its success is limited by severe side effects, transient response, and the high prevalence of relapse. Curcumin is a natural product found in the rhizome extract of Curcuma longa and has been extensively used over the last decades for its unique biological and medicinal properties, which include: having antioxidant, analgesic, anti-inflammation, and anti-tumor activities. Curcumin exerts its anticancer properties against ovarian cancer via multiple mechanisms: interfering with cellular interactions necessary for metastasis and recurrence of OC cells, increasing pro-apoptotic proteins as well as inducing or suppressing generation of different molecules such as cytokines, transcription factors, enzymes, protein kinases, and growth factors. Moreover, curcumin down-regulates various signaling pathways such as PI3K/Akt, Wnt/β-catenin, JAK/STAT3, and MEK/ERK1/2 axes, which at least in part have a role in inhibiting further tumor proliferation, growth, and angiogenesis. In this review, we overview the potential of incorporating curcumin into the treatment of ovarian cancer. In particular, we summarize the preclinical evidence supporting its use in combination with current chemotherapeutic regimens as well as new analogues and formulations under investigation.

Targeting microRNAs by curcumin: implication for cancer therapy

In spite of all the investigations in the past 20 years that established a great body of knowledge in cancer therapy, utilizing some elderly methods such as plant compound administration might still be useful. Curcumin is a bioactive polyphenol, which has many anticancer properties but its capability in modulating miRNA expression has opened new doors in the field of cancer-targeted therapy. MiRNAs are a class of small noncoding RNAs that are able to regulate gene expression and signaling. In addition, some other effects of these RNAs such as modulating cell differentiation and regulation of cell cycle have made miRNAs great candidates for personalized cancer treatment. In this review, we try to find some answers to the questions on how curcumin exerts its impacts on cancer hallmarks through miRNAs and whether chemotherapy can be replaced by this beneficial plant compound.

Curcumin anti-tumor effects on endometrial cancer with focus on its molecular targets

Curcumin is extracted from turmeric and shows a variety of properties that make it a useful agent for treating diseases and targeting different biological mechanisms, including apoptosis, angiogenesis, inflammation, and oxidative stress. This phenolic compound is safe even at high doses. However, it has poor bioavailability. The incidence rates of endometrial cancer (EC) that is one of the most prevalent gynecological malignancies is increasing. Meanwhile, the onset age of EC has been decreased in past few years. Besides, EC does not show a convenient prognosis, particularly at advanced stages. Based on this information, discovering new approaches or enhancing the available ones is required to provide better care for EC patients. In this review, we cover studies concerned with the anti-tumor effects of curcumin on EC. We focus on molecular mechanisms that are targeted by curcumin treatment in different processes of cancer development and progression, such as apoptosis, inflammation, and migration. Furthermore, we present the role of curcumin in targeting some microRNAs (miRNAs) that may play a role in EC.

Therapeutic role of curcumin and its novel formulations in gynecological cancers

Gynecological cancers are among the leading causes of cancer-associated mortality worldwide. While the number of cases are rising, current therapeutic approaches are not efficient enough. There are considerable side-effects as well as treatment resistant types. In addition, which all make the treatment complicated for afflicted cases. Therefore, in order to improve efficacy of the treatment process and patients’ quality of life, searching for novel adjuvant treatments is highly warranted. Curcumin, a promising natural compound, is endowed with numerous therapeutic potentials including significant anticancer effects. Recently, various investigations have demonstrated the anticancer effects of curcumin and its novel analogues on gynecological cancers. Moreover, novel formulations of curcumin have resulted in further propitious effects. This review discusses these studies and highlights the possible underlying mechanisms of the observed effects.

Antitumor effects and molecular mechanisms of action of natural products in ovarian cancer

Ovarian cancer is a common malignancy and the second leading cause of mortality among females with genital tract cancer. At present, postoperative platinum drugs and paclitaxel-based chemotherapy is the gold standard treatment for ovarian cancer. However, patients who receive this chemotherapy often develop cumulative toxic effects and are prone to chemotherapy resistance. Therefore, it is necessary to determine more effective treatment options that would be better tolerated by patients. Recent studies have reported the therapeutic effects of numerous natural products in patients with ovarian cancer. Notably, these natural ingredients do not induce adverse effects in healthy cells and tissues, suggesting that natural products may serve as a safe alternative treatment for ovarian cancer. The antitumor effects of natural products are attributed to suppression of cell proliferation and metastasis, stimulation of autophagy, improved chemotherapy sensitivity, and induction of apoptosis. The present review focused on the antitumor effects of several natural products, including curcumin, resveratrol, ginsenosides, (-)-epigallocatechin-3-gallate and quercetin, which are increasingly being investigated as therapeutic options in ovarian cancer, and discussed the molecular mechanisms involved in cell proliferation, apoptosis, autophagy, metastasis and sensitization.

Integrated analysis of gene expression and DNA methylation profiles in ovarian cancer

BACKGROUND

Ovarian cancer is an epithelial malignancy that intrigues people for its poor outcome and lack of efficient treatment, while methylation is an important mechanism that have been recognized in many malignancies. In this study, we attempt to assess abnormally methylated gene markers and pathways in ovarian cancer by integrating three microarray datasets.

METHODS

Three datasets including expression (GSE26712 and GSE66957) and methylation (GSE81224) datasets were accessed. GEO2R platform was used to detect abnormally methylated-differentially expressed genes. Protein-protein interaction (PPI) networks were built and analysed for hypermethylated and hypermethylated differentially expressed genes using Cytoscape software and Mcode app. GEPIA and cBioPortal platforms were used to validate the expression of the hub genes and the correlation between their mRNA expressions and methylation levels. Kaplan Meier-plotter platform were used to assess the prognostic significance of the hub genes.

RESULTS

Six hundred eighty-one hypomethylated-upregulated genes were detected and involved in Rap1 signaling pathway, biosynthesis of amino acids, endocrine resistance, apoptosis, pathways in cancer. The hub genes were TNF, UBC, SRC, ESR1, CDK1, PECAM1, CXCR4, MUC1, IKBKG. Additionally, 337 hypermethylated-downregulated genes were detected and involved in pathways in cancer, focal adhesion, sphingolipid signaling pathway, EGFR tyrosine kinase inhibitor resistance, cellular senescence. The hub genes were BDNF, CDC42, CD44, PPP2R5C, PTEN, UBB, BMP2, FOXO1, KLHL2. TNF, ESR1, MUC1, CD44, PPP2R5C, PTEN, UBB and FOXO1 showed significant negative correlation between their mRNA expressions and methylation levels. TNF, ESR1 and FOXO1 showed prognostic significance.

CONCLUSIONS

Two novel gene networks were found for ovarian cancer. TNF, ESR1, MUC1 and FOXO1 are our candidate genes that might take part in ovarian cancer progression in an epigenetic approach, TNF, ESR1 and FOXO1 may serve as potential markers for ovarian cancer prognosis evaluation.

Quercetin, Epigallocatechin Gallate, Curcumin, and Resveratrol: From Dietary Sources to Human MicroRNA Modulation

Epidemiologic studies suggest that dietary polyphenol intake is associated with a lower incidence of several non-communicable diseases. Although several foods contain complex mixtures of polyphenols, numerous factors can affect their content. Besides the well-known capability of these molecules to act as antioxidants, they are able to interact with cell-signaling pathways, modulating gene expression, influencing the activity of transcription factors, and modulating microRNAs. Here we deeply describe four polyphenols used as nutritional supplements: quercetin, resveratrol, epigallocatechin gallate (ECGC), and curcumin, summarizing the current knowledge about them, spanning from dietary sources to the epigenetic capabilities of these compounds on microRNA modulation.

Chinese Herbal Medicine-Based Cancer Therapy: Novel Anticancer Agents Targeting MicroRNAs to Regulate Tumor Growth and Metastasis

MicroRNAs, small non-coding RNA molecules, have gained a reputation of the most substantial regulators in gene network with the ability to down-regulate their targets. Accumulating evidence shifted insight toward microRNAs regulation as the key element of cancer initiation, development, and aggression. Recent studies have attached the importance of traditional Chinese medicine (TCM) to the treatment of various cancers, and the functional natural compounds have been considered as novel anticancer agents to directly inhibit tumor progression. In more recent decades, a wide range of biologically active components of TCM has gained increasing attention to their applications in the modulation of microRNAs. This review is on the purpose of demonstrating the significance of TCM bioactive ingredients in microRNAs regulation for cancer treatment according to the reports mainly in the recent six years, providing the evidence of efficient Chinese herbal medicine-based therapy and effective pro-diagnosis focusing on microRNAs expression of cancer patients.

Curcumin suppresses osteogenesis by inducing miR-126a-3p and subsequently suppressing the WNT/LRP6 pathway

Curcumin, a natural phenolic biphenyl compound derived from the plant Curcuma longa, modulates multiple steps of carcinogenesis partly by affecting the expression of miRNAs. Interestingly, cancer development shares many of the same signalling pathways with bone formation. Reduced bone mass creates favourable conditions for tumor metastasis. However, the effects and mechanism of curcumin on bone formation and osteogenesis are relatively unknown and controversial. We demonstrated that curcumin inhibited osteogenesis of human adipose-derived mesenchymal stem cells (hADSCs) in a concentration-dependent manner. In hADSCs, curcumin modulates the expression of a series of miRNAs, including miR-126a-3p, during osteogenesis. Overexpression or inhibition of miR-126a-3p is required for the effect of curcumin on osteogenesis. Further investigation indicated that miR-126a-3p directly targets and inhibits LRP6 through binding to its 3’-UTR, and then blocks WNT activation. Our findings suggest that the use of curcumin as an anti-tumor agent may lead to decreased bone mass through the suppression of osteogenesis. Knowing whether the long-term or high doses use of curcumin will cause decreased bone mass and bone density, which might increase the potential threat of tumor metastasis, also requires a neutral assessment of the role of curcumin in both regulating bone formation and bone absorption.

Curcumin as an Alternative Epigenetic Modulator: Mechanism of Action and Potential Effects

Curcumin (a polyphenolic compound in turmeric) is famous for its potent anti-inflammatory, anti-oxidant, and anti-cancer properties, and has a great potential to act as an epigenetic modulator. The epigenetic regulatory roles of curcumin include the inhibition of DNA methyltransferases (DNMTs), regulation of histone modifications via the regulation of histone acetyltransferases (HATs) and histone deacetylases (HDACs), regulation of microRNAs (miRNA), action as a DNA binding agent and interaction with transcription factors. These mechanisms are interconnected and play a vital role in tumor progression. The recent research has demonstrated the role of epigenetic inactivation of pivotal genes that regulate human pathologies such as cancers. Epigenetics helps to understand the mechanism of chemoprevention of cancer through different therapeutic agents. In this regard, dietary phytochemicals, such as curcumin, have emerged as a potential source to reverse epigenetic modifications and efficiently regulate the expression of genes and molecular targets that are involved in the promotion of tumorigenesis. The curcumin may also act as an epigenetic regulator in neurological disorders, inflammation, and diabetes. Moreover, curcumin can induce the modifications of histones (acetylation/deacetylation), which are among the most important epigenetic changes responsible for altered expression of genes leading to modulating the risks of cancers. Curcumin is an effective medicinal agent, as it regulates several important molecular signaling pathways that modulate survival, govern anti-oxidative properties like nuclear factor E2-related factor 2 (Nrf2) and inflammation pathways, e.g., nuclear factor kappa B (NF-κB). Curcumin is a potent proteasome inhibitor that increases p-53 level and induces apoptosis through caspase activation. Moreover, the disruption of 26S proteasome activity induced by curcumin through inhibiting DYRK2 in different cancerous cells resulting in the inhibition of cell proliferation opens up a new horizon for using curcumin as a potential preventive and treatment approach in proteasome-linked cancers. This review presents a brief summary of knowledge about the mechanism of epigenetic changes induced by curcumin and the potential effects of curcumin such as anti-oxidant activity, enhancement of wound healing, modulation of angiogenesis and its interaction with inflammatory cytokines. The development of curcumin as a clinical molecule for successful chemo-prevention and alternate therapeutic approach needs further mechanistic insights.

The targeting of non‑coding RNAs by curcumin: Facts and hopes for cancer therapy (Review)

Curcumin [(1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl) hepta-1,6-diene-3,5-dione] is a natural polyphenol that is derived from the turmeric plant (curcuma longa L.). Curcumin is widely used in food coloring, preservatives, and condiments. Curcumin possesses anti-tumor, anti-oxidative and anti-inflammatory efficacy, as well as other pharmacological effects. Emerging evidence indicates that curcumin alters microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in various types of cancers. Both miRNAs and lncRNAs are non-coding RNAs that can epigenetically modulate the expression of multiple genes via post-transcriptional regulation. In the present review, the interactions between curcumin and non-coding RNAs are summarized in numerous types of cancers, including lung, colorectal, prostate, breast, nasopharyngeal, pancreatic, blood, and ovarian cancer, and the vital non-coding RNAs and their downstream targets are described.

Synergistic Antiproliferative Effects of Co-nanoencapsulated Curcumin and Chrysin on MDA-MB-231 Breast Cancer Cells Through Upregulating miR-132 and miR-502c

In this study, we explored whether co-nanoencapsulated Curcumin (Cur) and Chrysin (Chr), natural herbal compounds with antitumor activities, regulate miR-132 and miR-502c and their downstream targets, leading to the synergistic growth inhibition in MDA-MB-231 breast cancer cells. For this purpose, Cur and Chr were co-encapsulated into PLGA-PEG nanoparticles (NPs) and characterized through DLS, FTIR and FE-SEM. MTT assay and cell cycle arrest analysis revealed that CurChr-loaded NPs had a considerable synergistic cytotoxicity against MDA-MB-231 cells with more cell accumulation in G2/M phase compared to the other groups. In addition, highest percentage of cell apoptosis was acquired in cells treated with CurChr-loaded NPs according to apoptosis analysis. Real-time PCR findings revealed that co-encapsulated form of Cur and Chr than free combination could further upregulate miR-132 and miR-502c expression (P < 0.001). Also, the strong reduction was detected in the protein levels of HN1 and P65 at the cells co-nanodelivered with Cur and Chr. These findings demonstrated that the co-nanodelivery of Cur and Chr through targeting miR-132 and miR-205c might be a novel strategy for the treatment of breast cancer.

Chemopreventive and therapeutic potential of curcumin in esophageal cancer: Current and future status

Esophageal cancer is a common malignant tumor with an increasing trend during the past three decades. Currently, esophagectomy, often in combination with neoadjuvant chemo- and radiotherapy, is the cornerstone of curative treatment for esophageal cancer. However, esophagostomy is related to significant risks of perioperative mortality and morbidity, as well as lengthy recovery. Moreover, the adjuvant therapies including chemotherapy and radiotherapy are associated with numerous side effects, limiting compliance and outcome. The dietary agent curcumin has been extensively studied over the past few decades and is known to have many biological activities especially in regard to the prevention and potential treatment of cancer. This review summarizes the chemo-preventive and chemotherapeutic potential of curcumin in esophageal cancer in both preclinical and clinical settings.

Effects of resveratrol, curcumin, berberine and other nutraceuticals on aging, cancer development, cancer stem cells and microRNAs

Natural products or nutraceuticals have been shown to elicit anti-aging, anti-cancer and other health-enhancing effects. A key target of the effects of natural products may be the regulation of microRNA (miR) expression which results in cell death or prevents aging, diabetes, cardiovascular and other diseases. This review will focus on a few natural products, especially on resveratrol (RES), curcumin (CUR) and berberine (BBR). RES is obtained from the skins of grapes and other fruits and berries. RES may extend human lifespan by activating the sirtuins and SIRT1 molecules. CUR is isolated from the root of turmeric (Curcuma longa). CUR is currently used in the treatment of many disorders, especially in those involving an inflammatory process. CUR and modified derivatives have been shown to have potent anti-cancer effects, especially on cancer stem cells (CSC). BBR is also isolated from various plants (e.g., Coptis chinensis) and has been used for centuries in traditional medicine to treat diseases such as adult- onset diabetes. Understanding the benefits of these and other nutraceuticals may result in approaches to improve human health.

Up-regulation of miR-21 decreases chemotherapeutic effect of dendrosomal curcumin in breast cancer cells

OBJECTIVES

Despite the good results of anticancer activities by curcumin, there are some hurdles that limit the use of curcumin as an anticancer agent. Many methods were examined to overcome this defect like the use of the dendrosomal curcumin (DNC). There is increasing evidence that miRNAs play important roles in biological processes. In this study, we focus on the roles of microRNA-21 in the anti-cancer effects of DNC in breast cancer.

MATERIALS AND METHODS

Also, we have used different methods such as MTT, apoptosis, cell cycle analysis, transwell migration assay and RT-PCR to find out more.

RESULTS

We observed that miR-21 decreased apoptotic cells in both cells (from 6.35% to 0.34 % and from 7.72% to 1.32% orderly) and DNC increased it. As well as, our findings indicated that cell migration capacity was increased by miR-21 over expression and was decreased by DNC. The combination of miR-21 vector transfection and DNC treatment showed lower percentage of apoptotic cells or a higher level of penetration through the membrane compared with DNC treatment alone. Furthermore, DNC induced a marked increase in the number of cells in sub G1/G1 phase and a decrease in G2/M phase of the cell cycle in both; but, we observed reverse results compared it, after transfection with miR-21 vector.

CONCLUSION

We observed that miR-21 suppress many aspects of anti-cancer effects of DNC in breast cancer cells, it seems that co-treatment with DNC and mir-21 down-regulation may provide a clinically useful tool for drug-resistance breast cancer cells.

Current state of phenolic and terpenoidal dietary factors and natural products as non-coding RNA/microRNA modulators for improved cancer therapy and prevention

The epigenetic regulation of cancer cells by small non-coding RNA molecules, the microRNAs (miRNAs), has raised particular interest in the field of oncology. These miRNAs play crucial roles concerning pathogenic properties of cancer cells and the sensitivity of cancer cells towards anticancer drugs. Certain miRNAs are responsible for an enhanced activity of drugs, while others lead to the formation of tumor resistance. In addition, miRNAs regulate survival and proliferation of cancer cells, in particular of cancer stem-like cells (CSCs), that are especially drug-resistant and, thus, cause tumor relapse in many cases. Various small molecule compounds were discovered that target miRNAs that are known to modulate tumor aggressiveness and drug resistance. This review comprises the effects of naturally occurring small molecules (phenolic compounds and terpenoids) on miRNAs involved in cancer diseases.

miR-9 Modulates Osteosarcoma Cell Growth by Targeting the GCIP Tumor Suppressor

Osteosarcoma is the most common primary bone tumor in humans, especially in childhood. However, the genetic etiology for its pathogenesis remains elusive. It is known that microRNAs (miRNAs) are involved in the development of tumor progression. Here we show that microRNA-9 (miR-9) is a potential oncogene upregulated in osteosarcoma cells. Knockdown of miR-9 in osteosarcoma resulted in suppressed colony formation and cell proliferation. Further study identified GCIP, a Grap2 and cyclin D interacting protein, as a direct target of miR- 9. In addition, GCIP overexpression activated retinoblastoma 1 (Rb) and suppressed E2F transcriptional target expression in osteosarcoma cells. Moreover, GCIP depletion reversed miR-9 knockdown induced colony formation and cell proliferation suppression. In sum, these results highlight the importance of miR-9 as an oncogene in regulating the proliferation of osteosarcoma by directly targeting GCIP and may provide new insights into the pathogenesis of osteosarcoma.

MicroRNAs: biogenesis, roles for carcinogenesis and as potential biomarkers for cancer diagnosis and prognosis

MicroRNAs (miRNAs) are short non-coding RNAs of 20-24 nucleotides that play important roles in carcinogenesis. Accordingly, miRNAs control numerous cancer-relevant biological events such as cell proliferation, cell cycle control, metabolism and apoptosis. In this review, we summarize the current knowledge and concepts concerning the biogenesis of miRNAs, miRNA roles in cancer and their potential as biomarkers for cancer diagnosis and prognosis including the regulation of key cancer-related pathways, such as cell cycle control and miRNA dysregulation. Moreover, microRNA molecules are already receiving the attention of world researchers as therapeutic targets and agents. Therefore, in-depth knowledge of microRNAs has the potential not only to identify their roles in cancer, but also to exploit them as potential biomarkers for cancer diagnosis and identify therapeutic targets for new drug discovery.

The beneficial role of curcumin on inflammation, diabetes and neurodegenerative disease: A recent update

The concept of using phytochemicals has ushered in a new revolution in pharmaceuticals. Naturally occurring polyphenols (like curcumin, morin, resveratrol, etc.) have gained importance because of their minimal side effects, low cost and abundance. Curcumin (diferuloylmethane) is a component of turmeric isolated from the rhizome of Curcuma longa. Research for more than two decades has revealed the pleiotropic nature of the biological effects of this molecule. More than 7000 published articles have shed light on the various aspects of curcumin including its antioxidant, hypoglycemic, anti-inflammatory and anti-cancer activities. Apart from these well-known activities, this natural polyphenolic compound also exerts its beneficial effects by modulating different signalling molecules including transcription factors, chemokines, cytokines, tumour suppressor genes, adhesion molecules, microRNAs, etc. Oxidative stress and inflammation play a pivotal role in various diseases like diabetes, cancer, arthritis, Alzheimer's disease and cardiovascular diseases. Curcumin, therefore, could be a therapeutic option for the treatment of these diseases, provided limitations in its oral bioavailability can be overcome. The current review provides an updated overview of the metabolism and mechanism of action of curcumin in various organ pathophysiologies. The review also discusses the potential for multifunctional therapeutic application of curcumin and its recent progress in clinical biology.

Impact of Nutrition on Non-Coding RNA Epigenetics in Breast and Gynecological Cancer

Cancer is the second leading cause of death in females. According to the American Cancer Society, there are 327,660 new cases in breast and gynecological cancers estimated in 2014, placing emphasis on the need for cancer prevention and new cancer treatment strategies. One important approach to cancer prevention involves phytochemicals, biologically active compounds derived from plants. A variety of studies on the impact of dietary compounds found in cruciferous vegetables, green tea, and spices like curry and black pepper have revealed epigenetic changes in female cancers. Thus, an important emerging topic comprises epigenetic changes due to the modulation of non-coding RNA levels. Since it has been shown that non-coding RNAs such as microRNAs and long non-coding RNAs are aberrantly expressed in cancer, and furthermore are linked to distinct cancer phenotypes, understanding the effects of dietary compounds and supplements on the epigenetic modulator non-coding RNA is of great interest. This article reviews the current findings on nutrition-induced changes in breast and gynecological cancers at the non-coding RNA level.

MicroRNA-9 promotes tumorigenesis and mediates sensitivity to cisplatin in primary epithelial ovarian cancer cells

MicroRNAs play critical roles in regulating tumor occurrence and drug sensitivity in ovarian cancers. This study aimed to investigate the key members of MicroRNAs (miRNAs) involved in modulating tumor initiation and drug resistance in primary ovarian cancer cells. An in vitro assay based on tumor clonal formation was established to evaluate tumorigenicity and cisplatin sensitivity. By performing real-time polymerase chain reaction, we examined the expression of nine microRNAs associated with the pathology of ovarian cancers in primary ovarian tumor cells, which were surgically resected from 46 patients with distinct sensitivity to platinum-based chemotherapy. MiR-9, miR-145, and miR-429 were expressed significantly higher in drug-sensitive patients (n = 26) than in drug-resistant ones (n = 20), while higher miR-26a expression was found in resistant patients (p < 0.05). In addition, tumor cells from drug sensitive patients were more tumorigenic than those of drug resistance (p = 0.0013). Cisplatin treatment led to a sharp decrease of clonal formation of drug-sensitive cells but showed slight effects on drug resistant cells. Specific anti-miRs were then employed to downregulate the expression of microRNAs in primary tumor cells. Inhibition of miR-9 resulted in decreased clonal formation and sensitivity to cisplatin, while the knockdown of other three microRNAs did not show any influence in tumorigenesis and drug sensitivity. In conclusion, this study showed that in primary ovarian tumor cells, high expression of miR-9 was associated with enhanced tumorigenesis and increased sensitivity of the tumor cells to cisplatin treatment.

Modulation of microRNAs by phytochemicals in cancer: underlying mechanisms and translational significance

MicroRNAs (miRNAs) are small, endogenous noncoding RNAs that regulate a variety of biological processes such as differentiation, development, and survival. Recent studies suggest that miRNAs are dysregulated in cancer and play critical roles in cancer initiation, progression, and chemoresistance. Therefore, exploitation of miRNAs as targets for cancer prevention and therapy could be a promising approach. Extensive evidence suggests that many naturally occurring phytochemicals regulate the expression of numerous miRNAs involved in the pathobiology of cancer. Therefore, an understanding of the regulation of miRNAs by phytochemicals in cancer, their underlying molecular mechanisms, and functional consequences on tumor pathophysiology may be useful in formulating novel strategies to combat this devastating disease. These aspects are discussed in this review paper with an objective of highlighting the significance of these observations from the translational standpoint.

Current Perspectives on Epigenetic Modifications by Dietary Chemopreventive and Herbal Phytochemicals

Studies during the last two decades have revealed the involvement of epigenetic modifications in the development of human cancer. It is now recognized that the interplay of DNA methylation, post-translational histone modification, and non-coding RNAs can interact with genetic defects to drive tumorigenesis. The early onset, reversibility, and dynamic nature of such epigenetic modifications enable them to be developed as promising cancer biomarkers and preventive/therapeutic targets. In addition to the recent approval of several epigenetic therapies in the treatment of human cancer, emerging studies have indicated that dietary phytochemicals might exert cancer chemopreventive effects by targeting epigenetic mechanisms. In this review, we will present the current understanding of the epigenetic alterations in carcinogenesis and highlight the potential of targeting these mechanisms to treat/prevent cancer. The latest findings, published in the past three years regarding the effects of dietary phytochemicals in modulating epigenetic mechanisms will also be discussed.

"Curcumin, the King of Spices": Epigenetic Regulatory Mechanisms in the Prevention of Cancer, Neurological, and Inflammatory Diseases

Curcumin (diferuloylmethane), a polyphenolic compound, is a component of Curcuma longa, commonly known as turmeric. It is a well-known anti-inflammatory, anti-oxidative, and anti-lipidemic agent and has recently been shown to modulate several diseases via epigenetic regulation. Many recent studies have demonstrated the role of epigenetic inactivation of pivotal genes that regulate human pathologies, such as neurocognitive disorders, inflammation, obesity, and cancers. Epigenetic changes involve changes in DNA methylation, histone modifications, or altered microRNA expression patterns which are known to be interconnected and play a key role in tumor progression and failure of conventional chemotherapy. The majority of epigenetic changes are influenced by lifestyle and diets. In this regard, dietary phytochemicals as dietary supplements have emerged as a promising source that are able to reverse these epigenetic alterations, to actively regulate gene expression and molecular targets that are known to promote tumorigenesis, and also to prevent age-related diseases through epigenetic modifications. There have been several studies which reported the role of curcumin as an epigenetic regulator in neurological disorders, inflammation, and in diabetes apart from cancers. The epigenetic regulatory roles of curcumin include (1) inhibition of DNA methyltransferases (DNMTs), which has been well defined from the recent studies on its function as a DNA hypomethylating agent; (2) regulation of histone modifications via regulation of histone acetyltransferases (HATs) and histone deacetylases (HDACs); and (3) regulation of micro RNAs (miRNA). This review summarizes the current knowledge on the effect of curcumin in the treatment and/or prevention of inflammation, neurodegenerative diseases, and cancers by regulating histone deacetylases, histone acetyltransferases, and DNA methyltransferases.

Potential application of curcumin and its analogues in the treatment strategy of patients with primary epithelial ovarian cancer

Recent findings on the molecular basis of ovarian cancer development and progression create new opportunities to develop anticancer medications that would affect specific metabolic pathways and decrease side systemic toxicity of conventional treatment. Among new possibilities for cancer chemoprevention, much attention is paid to curcumin—A broad-spectrum anticancer polyphenolic derivative extracted from the rhizome of Curcuma longa L. According to ClinicalTrials.gov at present there are no running pilot studies, which could assess possible therapeutic benefits from curcumin supplementation to patients with primary epithelial ovarian cancer. Therefore, the goal of this review was to evaluate potential preclinical properties of curcumin and its new analogues on the basis of in vivo and in vitro ovarian cancer studies. Curcumin and its different formulations have been shown to display multifunctional mechanisms of anticancer activity, not only in platinum-resistant primary epithelial ovarian cancer, but also in multidrug resistant cancer cells/xenografts models. Curcumin administered together with platinum-taxane chemotherapeutics have been reported to demonstrate synergistic effects, sensitize resistant cells to drugs, and decrease their biologically effective doses. An accumulating body of evidence suggests that curcumin, due to its long-term safety and an excellent profile of side effects should be considered as a beneficial support in ovarian cancer treatment strategies, especially in patients with platinum-resistant primary epithelial recurrent ovarian cancer or multidrug resistant disease. Although the prospect of curcumin and its formulations as anticancer agents in ovarian cancer treatment strategy appears to be challenging, and at the same time promising, there is a further need to evaluate its effectiveness in clinical studies.

Curcumin inhibits oral squamous cell carcinoma SCC-9 cells proliferation by regulating miR-9 expression

Curcumin, a phytochemical derived from the rhizome of Curcuma longa, has shown anticancer effects against a variety of tumors. In the present study, we investigated the effects of curcumin on the miR-9 expression in oral squamous cell carcinoma (OSCC) and explored the potential relationships between miR-9 and Wnt/β-catenin pathway in curcumin-mediated OSCC inhibition in vitro. As the results shown, the expression levels of miR-9 were significantly lower in clinical OSCC specimens than those in the adjacent non-tumor tissues. Furthermore, our results indicated that curcumin inhibited OSCC cells (SCC-9 cells) proliferation through up-regulating miR-9 expression, and suppressing Wnt/β-catenin signaling by increasing the expression levels of the GSK-3β, phosphorylated GSK-3β and β-catenin, and decreasing the cyclin D1 level. Additionally, the up-regulation of miR-9 by curcumin in SCC-9 cells was significantly inhibited by delivering anti-miR-9 but not control oligonucleotides. Downregulation of miR-9 by anti-miR-9 not only attenuated the growth-suppressive effects of curcumin on SCC-9 cells, but also re-activated Wnt/β-catenin signaling that was inhibited by curcumin. Therefore, our findings would provide a new insight into the use of curcumin against OSCC in future.

Curcumin inhibits cell growth and invasion through up-regulation of miR-7 in pancreatic cancer cells

Accumulating evidence has revealed that a natural compound curcumin exerts its anti-tumor activity in pancreatic cancer. However, the underlying molecular mechanism remains elusive. Recently, miRNAs have been demonstrated to play a crucial role in tumorigenesis, suggesting that targeting miRNAs could be a promising approach for the treatment of human cancers. In this study, we explored whether curcumin regulates miR-7, leading to the inhibition of cell growth, migration and invasion in pancreatic cancer cells. We observed that curcumin suppressed cell growth, migration and invasion, and induced cell apoptosis, which is associated with increased expression of miR-7 and subsequently decreased expression of SET8, one of the miR-7 targets. These findings demonstrated that targeting miR-7 by curcumin could be a novel strategy for the treatment of pancreatic cancer.